Inflatable tools have been used for abrading or finishing workpiece surfaces, such as by sanding, grinding, deburring, buffing, and polishing. Inflatable tools typically provide a flexible abrading surface that is preferred over rigid abrading surfaces. For example, rigid abrading surfaces often cause vibrating or chattering of the tool and workpiece, thereby causing damage to the tool and the workpiece, particularly when the workpiece surface is uneven. An inflatable tool provides a flexible abrading surface that yields to the workpiece surface to avoid chattering and damaging the workpiece surface.
Prior art inflatable tools, however, have not sufficiently met the needs of different types of abrading and machining and difference sizes and shapes of workpieces. One problem with many of the prior art inflatable tools is that they are overly complex and are limited in size. Such devices are also expensive to manufacture, difficult to use, and are limited in their use. Many prior art inflatable tools, for example, are not capable of being used to abrade or polish relatively small internal surfaces in a workpiece. The complex structure of many prior art inflatable tools does not permit the tools to be easily manufactured in a variety of sizes.
Another problem with prior art inflatable tools is that the inflatable abrading surface and the surface being abraded are often easily damaged. Prior art inflatable tools typically have a rigid surface beneath the inflatable abrading surface that causes damage to the inflatable abrading surface and the workpiece when the inflatable abrading surface is forced against the workpiece. A further deficiency of the prior art is the limited shapes of the flexible abrading surface. The prior art inflatable tools provide only a substantially cylindrical abrading surface that has limited abrading applications.
The inflatable tool 10 shown in FIG. 1 and disclosed in U.S. Pat. No. 5,672,096, incorporated herein by reference, has solved the above problems. The inflatable tool 10 may be used for machining or preparing a workpiece surface 2 including, but not limited to, grinding, honing, deburring, sanding, buffing, polishing, finishing, and chamfering. The inflatable tool 10 can be used with any type of machining or other process for preparing a workpiece surface including external surfaces, internal surfaces, flat surfaces, and irregular surfaces.
The inflatable tool 10 is rotatably driven about its longitudinal axis by a machine tool (not shown) such as a drill, air driven rotator, CNC machine or the like. For example, a shank 12 of the inflatable tool 10 is secured in a chuck or other similar tool holder of the machine tool. The inflatable tool 10 can be rotatably driven, for example, with a drill press, lathe, milling machine, hand-drill, air tool and any other rotatably driven machine tool. According to one example, the inflatable tool can be rotated up to 5000 RPM.
The inflatable tool 10 includes an inflatable tool surface 14, such as an abrasive surface, or any other type of workpiece altering surface used for grinding, deburring, honing, sanding, polishing, buffing, chamfering, finishing or otherwise preparing a workpiece surface. The inflatable tool 10 also includes a core 16 that supports the inflatable tool surface 14 and about which the inflatable tool surface 14 expands. The shank 12 is preferably coupled to a first core end 15 of the core 16. In one embodiment, a valve 18 is operatively coupled proximate a second core end 17 of the core 16, as will be described in greater detail below.
The inflatable tool 10, FIG. 2, includes a core 16 comprising an inner core portion 20 and an elastomeric outer core portion 22 disposed around the inner core portion 20. The inner core portion 20 is preferably made of a steel, such as cold roll-12L14-1018, or any other metal or suitable rigid materials.
The inflatable tool 10 further includes an inflatable member or bladder 30 sealably fixed or clamped to the first core end 15 and the second core end 17. In an inflated state, a chamber or pocket 32 containing a pressurized medium, such as air, water, gel, or the like, exists between the inflatable bladder 30 and the elastomeric outer core portion 22 of core 16. The inflatable bladder 30 disposed around the elastomeric outer core portion 22 is preferably made of a non-molded rubber material that allows the inflatable bladder 30 to be easily inflated.
The inflatable tool surface 14 is preferably provided by an abrasive sleeve 34 disposed around the inflatable bladder 30 and held in place by the inflatable bladder 30 when inflated. Abrasive sleeves 34, as used herein include, but are not limited to, any sleeve or belt used for sanding, grinding, buffing, polishing, honing, finishing, or any type of workpiece surface preparation. When the inflatable abrasive surface 14 contacts a workpiece surface (not shown), the pocket or chamber 32 allows the inflatable tool surface 14 to yield or deform to conform to the workpiece surface.
The elastomeric outer core portion 22 of core 16 provides a resilient surface 36 behind the inflatable tool surface 14. In a deflated state, the inflatable bladder 30 preferably lies against the resilient surface 36 of the elastomeric outer core portion 22. If the inflatable tool surface 14 is forced against a workpiece, for example, the resilient surface 36 on the elastomeric outer core portion 22 will provide a cushion and prevent damage to the workpiece, the inflatable bladder 30, and the inflatable tool surface 14, such as abrasive sleeve 34. The elastomeric outer core portion 22 is preferably made out of rubber, such as a vulcanized rubber of about 40 to 45 Durometer, or any other suitable elastomeric material.
A passageway 38 preferably extends through the inner core portion 20 and elastomeric outer core portion 22 so that the pressurized medium, such as air, can be provided to the pocket or chamber 32 to inflate the inflatable bladder 30. The valve 18 is coupled to an inflating device 40 that provides the pressurized medium through a valve passageway 42 in the valve 18. The valve passageway 42 is in fluid communication with the passageway 38 through the inner core portion 20 and elastomeric outer core portion 22. The valve 18 includes a coupling region 44 that operatively couples the valve 18 to the inflating device 40, for example, by threading the inflating device 40 into the valve coupling region 44.
The width and amount of cushion provided by the pocket or chamber 32 can be adjusted by varying the amount of pressurized medium, for example, within the range of about 0.02 to 0.4 inches wide. Varying the inflation thereby adjusts the diameter of the inflatable tool 10 and allows the abrasive sleeve 34 to be removed and replaced. The inflation and width of the chamber 32 can be varied to any degree depending upon the size of the inflatable tool and the desired application for the tool.
The inflatable tool 10 includes a first end clamping plate 50 that sealably clamps a first end 31 of the inflatable bladder 30 to the first core end 15, and a second end clamping plate 52 that sealably clamps a second end 33 of the inflatable bladder 30 to the second core end 17. A first engaging member 54 secures the first end clamping plate 50 to the first core end 15. In one example, the first engaging member 54 is disposed at one end of the shank 12 and is threadably engaged within the inner core portion 20. A second engaging member 56 secures the second end clamping plate 52 against the second core end 17, for example, by threadably engaging with the valve 18 which is threadably engaged within the inner core portion 20.
In one embodiment, the inflatable tool 10, FIG. 3, includes one or more bulging abrasive or workpiece finishing regions 60. According to this embodiment, the inflatable bladder 30 is preferably made from a non-molded rubber material such as tire inner tube material that facilitates the bulging. The bulging abrasive region 60 is preferably created by providing one or more slots 62 in an abrasive sleeve 64. The slots 62 allow the inflatable bladder 30 to expand to a greater diameter, thereby creating the bulging abrasive region 60.
The abrasive sleeve 64, FIG. 4, includes a sleeve portion 66 having one or more series of slots 62a, 62b extending substantially longitudinally in the sleeve portion 66 and circumferentially spaced around the sleeve portion 66. The slots 62a, 62b are preferably parallel and evenly distributed around the circumference of the sleeve portion 66. Each series of slots 62a, 62b are also spaced longitudinally along the sleeve portion 66 to form first and second bulging abrasive regions 60a, 60b, when the inflatable tool 10 is inflated.
One example of the abrasive sleeve 64 is sand paper having a sleeve portion 66 made of "Scotchbrite" material. The abrasive sleeve 64 can have various types of sleeve portions 66 with various types of surfaces used in grinding, honing, deburring, polishing, buffing, sanding, finishing, and other types of surface preparation.
Although the abrasive sleeve 64 having the slots 62 has provided a number of advantages, this abrasive sleeve 64 has some limitations in that the sleeve portion 66 is made of a non-stretchable material. The degree to which the abrasive sleeve 64 can bulge is thus limited by the inability of the sleeve portion 66 to expand. The bulging abrasive sleeve 64 reaches a point where any additional pressure will cause the sleeve portion 66 to rip. The abrasive sleeve 64 also does not work as well on larger diameters. The abrasive sleeve 64 (FIG. 3) does not expand all the way to the end, leaving unexpanded regions 65 and limiting the abrasive contact with the workpiece. Also, the strips of abrasive formed by the slots 62 may get caught on surface irregularities, causing damage to the abrasive sleeve 64.
Accordingly, what is needed is an expandable abrasive sleeve capable of expanding to a wider range of diameters without tearing and without getting caught on surface irregularities. A need also exists for an expandable abrasive sleeve that is capable of expanding more uniformly and generally to the ends of the abrasive sleeve to improve the abrasive contact with the workpiece and to conform better to larger diameters.